Stabilizing woven fabrics

ABSTRACT

Woven fabrics are stabilized by causing hot compressed air to pass at high velocity through a transverse region of a travelling or intermittently moving web of fabric for the purpose of generating static electricity in the fibers of the fabric. Subsequently the electrostatic charges are removed by moisturizing the fabric which is then dried.

United States Patent Burley 11] 3,719,450 51 March 6, 1973 STABILIZING WOVEN FABRICS Inventor: John Charles Burley, Brighton,

England Assignee: Myron Ackerman, Acton near Nan'twich, England Filed: Aug. 6, 1971 Appl. No.: 169,740

Foreign Application Priority Data Aug. 20, 1970 Great Britain ..40,l3l/70 June 17, 1971 Great Britain ..28451/71 us. ca ..s/149.2, 8/1493, 68/5 D 1111. c1 ..F2'6b 13/10 Field of Search....8/l49.2, 149.3; 34/37; 68/5 E, 68/5C,5D,5R,5A,5B

[56] References Cited UNITED STATES PATENTS 2,428,615 10/1947 Brown ..34 37 FOREIGN PATENTS OR APPLICATIONS 667,210 2/1952 Great Britain ..8/l49.3

Primary ExaminerWilliam I. Price Att0meyJ. Y. Houghton et al.

[5 7] ABSTRACT Woven fabrics are stabilized by causing hot compressed air to pass at high velocity through a transverse region of a travelling or intermittently moving web of fabric for the purpose of generating static electricity in the fibers of 'the fabric. Subsequently the electrostatic charges are removed by moisturizing the fabric which is then dried.

3 Claims, 2 Drawing" Figures STABILIZING WOVEN FABRICS This invention relates to stabilizing woven fabrics and has for its object to provide a stabilizing method which affords advantages of simplicity and inexpensive ness compared with known methods.

Although existing treatments are satisfactory in that the required relaxation of fibers is produced, the finish of the material usually suffers and additional treatment to restore the finish is then involved. Considerable expenditure of time and money is incurred in treating fabrics by the known methods and in the case of the water immersion process in common use the equipment currently employed is bulky and cumbersome.

According to the present invention, a method of stabilizing woven fabrics comprises the stepof generating static electricity within the fibers of the fabric to effect agitation and reorientation of the fibers thereby relaxing the fabric. In a particular method according to the invention the generation of the static electricity is produced by causing air heated and compressed to move at high velocity past the individual fibers of which the fabric is composed thereby producing friction resulting in the generation of static electrical charges within the fiber molecules.

Further according to the invention, a method of removing from the woven fabric the static electricity generated'comprises the step of moisturizing fibers.

Further according to the invention, apparatus for producing stabilization in a roll of woven fabric includes means for continuously moving the fabric from a supply spool to take-up rolls, means for applying hot compressed air to a localized transverse region of the length of fabric between the supply spool and take-up rolls, means for supplying moisture to the fabric in a transverse region thereof down stream of said localized region and means for subsequently extracting the moisture from the fabric.

In a particular-form of apparatus embodying the invention the means for applying the hot compressed air comprise a tube formed with a longitudinal slot and disposed transversely with respect to the length of fabric and the means for extracting the moisture from the fabric comprise a second tube formed with a longitudinal slot, said second tube being coupled to suetion producing means.

An alternative form of apparatus according to the invention includes means for intermittently moving the fabric from a supply spool to take-up rolls, means for applying hot compressed air to an area of the fabric while the fabric is temporarily stationary, the area being determined by the width and a selected length of the fabric, means for applying moisture to said area of the fabric after the application of hot air thereto and means for subsequently removing the moisture from the fabric. .The alternative form of apparatus referred to includes an open topped chamber, a sheet of mesh material mounted at the open top of the chamber and providing support for the area of fabric to be treated, means for supplying hot compressed air to said chamber and further means for supplying steam to said chamber. The apparatus is provided with a structure such as a cow] mounted for vertical movement with respect to the top of the chamber hand adapted, during operation of the apparatus, to rest in an air-tight sealing manner on the fabric, said structure or cowl being provided with suction producing means.

While a degree of stabilization of fabrics woven from, for example, wool, can be achieved by the; generation of static electrical charges within thefabric, improved results are obtained by subsequently treating the fabric to a moisturizing process for the purpose of completely eliminating the electrostatic charges. Thesteps to be described accordingly deal with. the behavior in fabrics from the completely. dry stateto that obtaining when they have absorbed acertain percentage of moisture. Thus, from the dry state wool fibers can absorb up to 35 percentof their own'weight of water swelling to about 16 percent indiameter and 1 percent in length resulting in changes of length and width in the wool fabric. These changes in dimensions. can include'an irreversible component known as relaxation shrinkage and-this is brought about in part by the generation of the electrostatic charges.

As already indicated, the heated air moving at high velocity past the individual fibers which comprise the fabric produces friction therein resulting inv minute, static electrical charges being generated in. the molecules of the wool and these together with the molecules of its residual grease are, in consequence, placed in a state of agitation causing their reorientation and finally, stabilization of the fibers. The process may apply to fabrics other than those woven wholly from wool, and the treatment of these by the process is included in the scope of the present invention.

Advantageously, the process must be efficacious in stabilizing woven fabrics of all the densities and varie ties likely to be found in production and this is achieved by providing an accurate control of the air pressure, the temperature to which the air is raised and. the rate of travel of the fabric over the transverse region of treatment. The adjustment of these three variables will enable' the operator to select the correct conditions appropriate to the particular fabric to be treated and after short test lengths have established the correct settings, thereafter these settings can be applied to fabrics of a similar type.

The slot through which the. heated compressed air is directed is covered by a perforated material, for example, stainless steel mesh with sufficient clearance between the surface of the mesh and the slotted tube for the smooth transfer of the fabric being treated, but close enough to hold the cloth against the slot despite the pressure of the heated air, thereby preventing lift and escape of air. To supplement the electric charge generated and held within the fabric momentarily by the first part of the process, the woven material may be passed over and under a series of non-conductive round ebonite rods before reaching the second or moisturizing part of the process as explained hereinafter.

The moisturizing step deals with a second component in the behavior of wool fabrics. This is reversible and is called hygral expansion. It results from the fabric absorbing moisture and this technique is now described.

After leaving the localized transverse region on'the completion of the first part of the process and passing over the ebonite rollers the fabric is now in a completely dry state. While still partially expanded in web form, moisture is induced into it preferably in the form of steam and with the fibers momentarily isolated from each other they present a maximum area for treatment resulting in even and rapid processing.

This operation may be performed by passing the fabric over a second localized transverse region and again this may take the form of a slot extending across the width of a platform or tube supporting the fabric and which in this case is coupled to a vacuum pump for vthe purpose of removing surplus moisture. After this moisturizing process is complete it will be found to have added to the irreversible component i.e. relaxation shrinkage and at the same time to have removed any traces of static electricity generated during the first part of the process, the fabric during these operations being drawn through by rolls which may be heated metal rolls or hollow cylinders which also complete the drying out of the wool fibers.'

It will be apparent from the foregoing description of a method of applying the invention that the process involves the continuous transfer of the woven fabric from the supply spool to the take-up spools or rolls, a narrow strip being dealt with at each point in its travel. If it is desired to increase the speed of treatment, the narrow slot construction can be substituted by a steel meshcovered frame to accommodate the standard width of woven fabric, the length of frame determining the area of fabric to be treated at any one time and ultimately the process speed. While the fabric is being transferred from the supply spool to the take-up rolls and passing over this frame the travel is halted temporarily, the

dwell period being predetermined to suit the type of fabric being treated. A cowl is lowered over the treatment area to provide an airtight seal during the dwell period when the compressed hot air treatment and the subsequent moisturizing treatment completes the process which is identical in principle with that which takes place in the narrow slot construction.

Alternative embodiment of the invention will now be described in greater detail by way of example, with reference to the accompanying drawing in which:

FIG. 1 shows a side elevation of the localized transverse region method employing slotted tubes; and

FIG. 2 shows the alternative form of the apparatus in which the transverse region is greatly increased in area and covered by a cowl.

Referring to the drawings, and as shown in'FIG. 1, a supply spool 1 carries a roll of woven fabric shown as a broken line 2 and this fabric as it unwinds passes over'a support in the form of a slotted tube 3 which provides a localized transverse region through which hot compressed air is forced and a curved frame 4 covered with steel mesh contoured to a segment of tube 3 holds the fabric against the slot.

The continuously moving fabric while over this region has its hygral expansion component reduced to zero and the high velocity heated air moving past the individual wool fibers produces friction therein resulting in minute static electrical charges being generated which contribute to and amplify the relaxation process. These electrical charges c an be reinforced by drawing the fabric over a series of non-conductive rods 5 such as ebonite.

A row of jets 6 cause steam to impinge on the fabric the moisture thus deposited being drawn through it and through the slot in tube 7 to which a vacuum pump is con led the water extracted passing away to a waste out et. The moisturizing treatment ust described removes all traces of static electricity from the woven fabric, which is drawn through take up rolls 8 which may be heated to restore finish.

In FIG. 2 the supply spool 1 carries the roll of woven fabric, shown as a broken line 2 and this fabric as it unwinds passes over a platform of steel mesh 9 which rests on an open topped box-like structure or chamber 10 enclosing a cluster of jets l 1 coupled to a steam supply and also attached to an inlet pipe 12 from a heated compressed air supply. A cowl 13 located over the platform of steel mesh 9 is capable of being raised or lowered in a vertical direction and this also has its base covered with steel mesh to prevent lift of fabric.

In this form of the apparatus the woven fabric does not travel continuously from supply spool to take-up rolls but has a dwell period when an untreated section of fabric has completely covered the platform 9. The heated compressed air is pumped through the inlet pipe 12 into the chamber 10 and is driven through the fabric at high velocity, the cowl being in its lowered position during this part of the process and forming an air-tight seal against the woven fabric.

The hygral expansion component is reduced to zero and static electricity is generated within the wood fibers as already described in the form of construction first described. After the requisite period of time has elapsed, the steam supply is turned on and the jets 11 are directed against the fabric covering the whole of the treatment area this removing all traces of static.

electricity.

The cowl 13 has an outlet pipe 14 which is connected to a vacuum pump and suction begins to operate simul taneously with the turning on of the steam supply and continues some time after the steam supply has been turned off thus removing surplus moisture. The moisture removal operation can be assisted if required by cutting in for a short period the compressed air supply through the inlet pipe 12 but with the temperature lowered to a suitable degree The woven fabr-icvis then pulled through the rolls 8 to enable a fresh untreated length of cloth to be presented to the treatment area, the cowl 13 being raised during this operation to allow free traverse of the fabric.

1 claim: 1

1. A method of stabilizing woven fabrics comprising the step of generating static electricity within the fibers of the fabric to efiect agitation and reorientation of the fibers thereby relaxing the fabric. a

2. A method according to claim 1 comprising the step of causing air heated and compressed to move at high velocity past the individual fibers of which the fabric is composed thereby producing friction resulting in the generation of static electrical charges within the fiber molecules.

3. A method of removing from the woven fabric the static electricity generated by carrying out the method of claim 1 comprising the step of moisturizing the fibers.

"UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 7 6 Dated March 6, 1973 lnventofls) John Charles Burley It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

(1) Caption Page, item 59], for "2851/71" read mu/71 (2) Col.' 1, lines 2 and 1L4; col. 1;, line I 9; for "fabrics" read --woolen fabrics-- (3) 0'01. l line 29, for "woven" read --such woven-- (LL) Col. 2' line 28, for "and the", read --the-- line for "invention." read --invention, and the term "woolen fabrics" as herein used is to be so construed.

(5) Col. 3, line 6 for "fabric" read --woolen fabric-- Signed and sealed this 2nd day of April 1971+.

(SEAL) Attest:

EDWARD M.FLET CHER,JR. C. MARSHALL DANN Attesting Officer I Commissioner of Patents ORM PO-IOSO (10-69) USCOMM-DC 60376-P69 a us. GOVERNMENT PRINTING OFFICIE: I969 o-asa-su 

1. A method of stabilizing woven fabrics comprising the step of generating static electricity within the fibers of the fabric to effect agitation and reorientation of the fibers thereby relaxing the fabric.
 2. A method according to claim 1 comprising the step of causing air heated and compressed to move at high velocity past the individual fibers of which the fabric is composed thereby producing friction resulting in the generation of static electrical charges within the fiber molecules. 